1. Technical Field
The present invention relates to a light emitting apparatus, electronic equipment and a method of driving a pixel circuit.
2. Related Art
In recent years, an organic light emitting diode device (hereinafter, referred to as “OLED device”) which is also referred to as an electroluminescent (EL) device or a light emitting polymer device attracts attention as a next-generation light emitting device alternative to a liquid crystal device. Gradation (typically, brightness) of the light emitting device of this type changes when an electric current is supplied to the light emitting device. A configuration in which the current is controlled by a driving transistor has been proposed hitherto.
A pixel circuit of the light emitting apparatus disclosed in Japanese Patent No. 4,131,227 includes a light emission control transistor between the driving transistor and the OLED device. Further, the pixel circuit disclosed in Japanese Patent No. 4,131,227 includes a switching transistor between a node and a constant potential line. In this case, the node is provided between the light emission control transistor and the light emitting device on a driving current path. With this configuration, a current can be prevent from being supplied to the OLED device at the non-lighting time by turning the light emission control transistor in an OFF-state. In addition, faint light emission due to a leakage current of the light emission control transistor is prevented by turning the switching transistor in an ON-state. Therefore, so-called “black floating” phenomenon can be suppressed.
In the light emitting apparatus disclosed in Japanese Patent No. 4,131,227, when writing of a data potential is completed, the switching transistor is set to be in an OFF-state while the light emission control transistor is set to be in an ON state. At this time, a timing at which the switching transistor is turned to be in the OFF-state is substantially the same as a timing at which the light emission control transistor is turned to be in the ON-state. Therefore, charges left in a node between the driving transistor and the light emission control transistor when the writing of a data potential is completed are flown into the OLED device at the start of a light emission period. This causes a problem that undesired light emission is instantaneously caused. Note that the undesired light emission is different from intended light emission occurred when the driving current is supplied.